<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>

    <!-- 内嵌式 -->
    <script>
        // js 单行注释
        var iNum = 10;
        var sStr = "hello";
        var iNum1 = 10.5, sStr1 = 'world';
        alert(iNum);
        alert(iNum1);
        alert(sStr);
        alert(sStr1);
        console.log(iNum);
        console.log(iNum1);
        console.log(sStr);
        console.log(sStr1);

        // boolean
        var bIsOK = true;
        alert(typeof(bIsOK));

        var nData = null;
        console.log(nData);
        // 查看null对象的类型返回的是object类型，其实是null类型，
        // 由于js历史的原因没有返回null类型，因为之前没有null类型
        alert(typeof(nData));

        var oStudent = {
            name: "张三",
            age: 20
        };
        alert(typeof(oStudent));
        
    </script>
</head>
<body>
    
</body>
</html>